The invention generally relates to robotic systems, and relates in particular to robotic systems having an articulated arm with an end effector that employs vacuum pressure to engage objects in the environment.
Most vacuum grippers employ vacuum pressures well below 50% of atmospheric pressure, and are referred to herein as high vacuum. A typical source for a high vacuum gripper is a Venturi ejector, which produces high vacuum but low maximum air flow. Because of the low flow, it is essential to get a good seal between a vacuum gripper and an object, and it is also important to minimize the volume to be evacuated.
Suppliers of ejectors and related system components include Vaccon Company, Inc. of Medway, Mass., Festo US Corporation of Hauppauge, N.Y., Schmalz, Inc. of Raleigh, N.C. and others. In some instances where a good seal is not possible, some systems use high flow devices. Typical high flow devices are air amplifiers and blowers, which produce the desired flows, but cannot produce the high vacuum of a high vacuum source. High flow sources include the side-channel blowers supplied by Elmo Rietschle of Gardner, Denver, Inc. of Quincy, Ill., Fuji Electric Corporation of America of Edison, N.J., and Schmalz, Inc. of Raleigh, N.C. It is also possible to use air amplifiers as supplied by EDCO USA of Fenton, Mo. and EXAIR Corporation of Cincinnati, Ohio. Multistage ejectors are also known to be used to evacuate a large volume more quickly, wherein each stage provides higher levels of flow but lower levels of vacuum.
Despite the variety of vacuum systems, however, there remains a need for an end effector in a robotic system that is able to accommodate a wide variety of applications involving engaging a variety of types of items. There is further a need for an end effector that is able to provide high flow vacuum using a gripper that is able to handle a wide variety of objects.